Don wrote:
This is typical for an underdamped second order servo. The oscillation is the penalty for a shorter settling time. A critically damped system would not oscillate, but approach the final value smoothly in a slightly longer time. It may have been designed for a slight overshoot...
Yes, I understand and I don't doubt that it is performing as designed. My point was that most crystal oscillator frequency adjustments (at least, the ones that I have seen) are open-loop (variable capacitor or pot to a varactor diode). Finding the fine frequency control apparently in a servo loop was a surprise. And it cannot be a PLL or FLL, because there is only the one reference -- the one you are adjusting. Since the startup dynamics are so similar to the fine frequency adjustment dynamics (not to mention that the oven loop is pretty much the only possible servo in the oscillator), the evidence appears strong that the fine frequency adjustment is an oven temperature adjustment. Unless there is something truly diabolical going on inside a 9462.
Best regards, Charles _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
